The Electron Glass in a Switchable Mirror: Relaxation, Aging and Universality

Abstract

The rare earth hydride YH$_{3-δ}$ can be tuned through the metal-insulator transition both by changing $δ$ and by illumination with ultraviolet light. The transition is dominated by strong electron-electron interactions, with transport in the insulator sensitive to both a Coulomb gap and persistent quantum fluctuations. Via a systematic variation of UV illumination time, photon flux, Coulomb gap depth, and temperature, we demonstrate that polycrystalline YH$_{3-δ}$ serves as a model system for studying the properties of the interacting electron glass. Prominent among its features are logarithmic relaxation, aging, and universal scaling of the conductivity.